The present invention is directed to microcontrollers and, more particularly, to a method of resetting and booting a microcontroller in low power mode.
Power critical applications, such as in medical devices, metering devices, and the like, do not often include power sources capable of generating high currents. Thus, a microcontroller unit (MCU) in the device must ration the current among all resources requiring power consumption. Reset and boot cycles for the MCU can present a problem with power consumption. For example, the MCU in a device may require 16-18 milliAmperes (mA) of current while the existing power source can budget no more than 7 mA.
The main contributors to power drain during reset and boot sequences of the MCU are the flash memory, the system-on-chip (SoC) logic and the number of peripherals that are active following the reset sequence, and the use of a high frequency clock source during the boot sequence.
It is desirable to provide an MCU and a method of resetting and booting the MCU that requires less power and could therefore be used in current limited applications.